Control for oil well pumping equipment



1944- M. H. HALDERSON 2,360,561

CONTROL FOR OIL WELL PUMPING EQUIPMENT Filed Dec. 30, 1940 2Sheets-Sheet 1 INVENTOR M. H. HALDERSON BY 71%, gm 5Z4 ar/ ATTORNEPatented Oct. 17, 1944 CONTROL FOR OIL WELL PUMPING EQUIPMENT Maxwell H.Halderson, Smackover, Ark., assignmto Phillips Petroleum Company, acorporation of Delaware Application December 30, 1940, Serial No.372,408

3 Claims.

This invention relates to apparatus for automatically shutting downprime movers when operating conditions become abnormal.

When the reservoir energy of a hydrocarbon oil-bearing formation is notsufficient to lift the oil from the reservoir to the surface of theground some means of artificial lift is employed. A common type ofartificial lift is the well known reciprocating bottom hole pump whichis actuated by, a string of sucker rods extending down wardly from thesurface of the ground. A pumping unit, rig front, or the like, having anoscillatory member or walking beam is one of the devices generally usedto transmit energy from a prime mover to the polished rod andreciprocating pump.

In pumping fluids by this method, fatigue stresses or corrosion weakenthe string of sucker rods, causing them eventually to break. In wellsproducing appreciable quantities of sand or other solid materials alongwith the crude oil, the pumps may sand up and stick, causing the suckerrods to part or to become disconnected from the walking beam of thepumping unit. The parting of sucker rod strings puts abnormal stresseson the pumping unit or rig front since this surface equipment iscounterbalanced to re ciprocate the sucker rods at minimum peak loads.Consequently, when the sucker rods part or become disconnected from thesurface equipment, this equipment is thrown out of balance, and stressesfar exceeding the safe working limits result, and if operation isallowed to continue under these abnormal conditions, serious damage tothe surface equipment may result.

As the oil Wells usually pump a considerable length of time unattended,some means of automati'cally shutting down the prime mover is verydesirah- There are a number of devices which attemp to accomplish thisresult, however, none is entirely satisfactory.

The advantages of the present invention are its direct action, itssimple, compact design, its adaptation to a wide variety of operatingconditions, and its faculty for quick resetting.

The primary object of my invention is to provide a device forautomatically shutting down a prime mover when operating conditionsbecome abnormal. I

Another object of my invention is to provide a device that will shutdown a well pumping prime mover in the event the sucker rods part.

A still further object of my invention is to provide a compact,simply-designed shut-down device that is positive in action, dependablein operinvention. While the present description of the invention isdirected to its use with an oil well pumping unit, it is to be clearlyunderstood that this is merely by way of illustration as my inventionperforms its intended functions in a wholly satisfactory manner whenemployed with various other types of equipment.

Figure l is an elevation view of oil well pumping equipment with theapparatus of my inven tion operatively connected thereto.

Figure 2 represents an elevation view of one embodiment of my invention,partly in cross sec= tion, showing the device in the set position.

Figure 3 is a portion of the device, partly in cross section,illustrating the adaptation of my invention to shutting down an internalcombustion engine. This figure shows the device in tripped position.

Figure 4, which is an elevation view, represents a portion of anotherembodiment of my inverr tion that may be used where an open electric arcwould create a fire'hazard.

Referring to Figure l, a pumping unit, generally represented byreference numeral H, is driven by a prime mover it, which in thisembodiment is shown as an electric motor. Polished rod l3, which is theuppermost member of a string of sucker rods, reciprocates through wellhead fittings M to actuate a common type of bottom hole pump (notshown). The polished rod is suspended in the usual manner from a walkingbeam i5 which is operated from a crank it by means of a pitman ll. Agear reduction unit 18 transmits energy from motor 2 to crank it.Counterweights it are employed to balance the uneven loads to whichpumping unit it would otherwise be subjected, and thus provide asubstantially even operation of the pumping unit. An automatic shut-downdevice 2@ is secured to the forward end of walking beam and is connectedto prime mover E72 by electric leads 28.

Referring to Figure 2, a pivot pin 22 is pro= vided on shut-down device2t and serves as a fulcrum for an L-shaped lever 23 which has asubstantially horizontal arm whereupon a slidable weight 24 is mountedand secured thereto by means of a screw 25. .The substantially verticalarm of lever 23 is preferably provided with a foot 25 on its lower end.This foot is notched at 28 and is so designed that it cooperates withone end of a contact lever 21 to maintain it in one predeterminedposition when the pumping system as a whole is operating in a normalmanner and to maintain it in a second predetermined position when device20 has been actuated to shut-down the prime mover under abnormaloperating conditions. The vertical arm of lever 23 carries an eye 2%,preferably midway between pivot 22 and notch 28. A coil spring connectsat one end to eye 29 and at the other end to an eyebolt 3! which isfastened to a housing or case 32, which encloses the device, by nuts 33.The tension in spring 30 may be adjusted by changing the positions ofnuts 33 on eyebolt 3!.

A second pivot pin 34 serves as a fulcrum for lever ill. A spring 35,preferably in tension, insures Within desired limits, the turning oflever 2? about its pivot 34. A latch member 36, operable from theexterior of case 32, is attached to the left end of lever 2'5 so thatthe attendant may readily set my device initially, or reset the sameafter a shut-down by merely pulling downwardly on this latch, therebyeliminating the necessity of opening the case to set or reset thedevice. The movement of the right or tripping end of lever 21 is limitedby stops 31 provided in case 32. Theswitch mechanism of this deviceconsists of conductors or leads 28, one of which is connected to astationary contact point 38, the other to a conductor member 39 whichhas a contact point All on one end and which is secured at the other endto lever 21. In this embodiment wherein the pumping unit it is driven byan electric motor it, leads 28 are part of the power circuit to theelectric motor. Therefore, point it contacts point to to complete theelectric circuit. Thus, the pumping unit will operate only when thedevice 28 is in the set position.

Turning next to Figure 3, it is obvious that the instant invention isalso adapted to shutting down an internal combustion engine byconnecting leads 2i to the engines magneto and by keeping fixed contactpoint at and movable contact point 45 of conductor member 46 separatedwhile the pumping unit is operating. Thus, when the device 20 isactuated, point 45 contacts point id to short circuit the magneto andthereby shut down the prime mover.

In operation, returning to Figure 2, device 20 is secured to the walkingbeam of pumping unit l 5, preferably as near the polished rod it aspossible. The tension in spring 3b is adjusted to compensate for theordinary irregularities of pumping conditions. Thus, only the abnormalconditions of the pumping cycle will cause the device 2! to be actuatedand to shutdown prime mover l2. By changing the distance between weight24 and pivot 22, further sensitivity of the device may be obtained.Having adjusted the device to properly operate under the usualwellpumping conditions, pumping unit ii is placed in operation and thedevice oscillates with walking beam idbut remains in the set positionuntil the sucker rods part or some other abnormal condition ariseswhereby the acceleration of device it becomes abnormal. When the suckerrods part, the rod end of the walking beam 65 is accelerated upwardly ata rate which exceeds that of normal pumping conditions. The device 20 isaccelerated with the walking beam, but the weight 24, due to itsinertia, lags behind the rest of the device. Hence, the weight causeslever 23 to turn about pivot pin 22 in a counter-clockwise direction,thus moving foot 28 suificiently to the right to allow the tripping endof lever 21 to hecome disengaged from lever 23 at notch 23. Spring 35exerts an upward force on the left or resetting end of lever 21 andtends to rotate the lever clockwise about pivot 34. Thus, when thetripping end of lever 21 disengages notch 28, the electric motor is shutdown because conductor member 39 with contact point 40 is rotated awayfrom stationary contact 38, breaking the electric circuit. After lever23 has rotated about pivot 22, and lever 21 about pivot 34, spring 30pulls lever 23 back to a position, as illustrated in Figure 3. Thedesign of foot 26 allows cooperation with the upper edge otthe trippingend of lever 21 in such a manner that contact points 38 and 40 willremain separated until device 2!! is manually reset by a downward pullon resetting means 3d. The proper design of the tripping end of lever 2iand foot 26 also facilitates the resetting of the device.

If the device is adapted to shutting down the prime mover of theinternal combustion type, it is necessary to place contact point 44above contact 45 so that the two points are separated while the deviceis in a set position. When the device is actuated, point 45 movesupwardly as lever 21 rotates clockwise about its pivot and engagesstationary contact 44, closing a circuit between the device and themagneto of the internal combustion engine, grounding the magneto andthus shutting down the prime mover. If the internal combustion engineutilizes a storage battery, 9. high tension coil, and a distributor,rather than a magneto to obtain the electric spark for igniting theexplosive mixture in the cylinder of the en glue, the leads from thebattery may be wired through the device 20 and the contact points 44 and45 arranged in the manner disclosed for shutting down an electric motor,as illustrated in Figure 2.

Another embodiment of part of my invention, illustrated. in Figure 4,may be used where the atmosphere contains sufficient gas to be explosiveand where an open electric arc would create a fire hazard. An enclosedswitch 4!, preferably of the Mercoid type, is secured to lever 21 by asuitable mounting 42 so that after device 20 is actuated, the electriccircuit is broken or made, as desired, depending upon the type of primemover used for powering the pumping unit.

The operation of this embodiment is identical to that of otherembodiments heretofore described. In this instance, however, theelectric switching takes place Within tube 4! which utilizes a fluidelectric conductor, such as mercury, to make and break contact betweenlead 2i.

From the foregoing, it is believed that the operation and advantages ofthe apparatus for practicing my instant invention will be readilycomiggehended by persons skilled in the art. It is to changes in theapparatus herewith shown and described may be resorted to withoutdeparting from the spirit of the invention, as defined by'the appendedclaims.

I claim:

1. In a device of the character described adapted to be carried by awalking beam, the combination comprising a housing, a member pivotallyclearly understood, however, that various.

supported within the housing and including a plurality of arms, aswitch, means within the housing for operating the switch, said meansengagin: one arm of the pivotally supported member to maintain theswitch and the member in a predetermined fixed position under normaloperating conditions of the walking beam; means including a weight onanother arm of the pivotally supported member for disengaging said meansfrom the first mentioned arm under abnormal operating conditions of thewalking beam to thereby operate the switch, and means operable from theexterior of the housing. for efiecting engagement between the firstmentioned means and the pivotally supported member.

2. In a device of the character described adapted to be carried by awalking beam, the combination comprising a housing, a member pivotallysupported within the housing and including a plurality of arms, aswitch, a second member pivotally supported within the housing foroperating the switch, said second member engaging one arm of the firstmember to maintain the switch and the first member in a predeterminedfixed position under normal operating conditions of the walking beam,means including a weight on another arm of the first member fordisengaging the pivotally supported members under abnormal operatingconditions of the walking beam to thereby operate the switch, and meansoperable from the exterior of thehousing foreffecting engagement betweenthe pivotally supported members.

3. In a device of the character described adapted to be carried by awalking beam, the combination comprising a housing, a member pivotallysupported within the housing and including a plurality of arms, a springfor urging the member in a predetermined direction,a switch, a secondmember pivotally supported within the housing for operating the switch,a spring for urging the second member in a predetermined direction, saidsecond member engaging one arm of the first member against the action ofthe springs to maintain the switch in a predetermined position undernormal operating conditions of the walking beam,

means including a weight on another arm of the first member fordisengaging the pivotally supported members under abnormal operatingconditions of the walking beam, and means operable from the exterior ofthe housing for effecting engagement between the pivotally supportedmembers.

MAXWELL H. HALDERSON.

